1. Field of the Invention
The present invention relates to a process and an apparatus for respectively processing printing products arriving in an imbricated formation, in particular multisheet and folded printing products such as newspapers, periodicals and the like.
2. Description of the Related Art
Apparatus for processing printing products arriving in an imbricated formation are known, for example, from DE-A 2,820,957 and CH-A 566,925. The printing products are conveyed to a processing station by means of a belt conveyor in an imbricated formation in which each printing product lies on the preceding one. The processing station has an extraction arrangement arranged above the belt conveyor and on which a tongue-shaped switch element is provided which, in order to detach individual or several successive printing products (in particular spoiled copies) from the imbricated formation, may be lowered so as to be inserted into the imbricated formation and reach underneath the printing products to be detached at their leading edge running at right angles to the conveying direction. The printing products deflected upwards by means of the switch element are then taken up and conveyed away by accelerating belts. In order to expose the leading edge of the printing products, the imbricated formation may be guided over a step in the belt conveyor.
Each time the detaching of printing products is complete, the extraction arrangement is to be raised upwards in order to free the last deflected printing product, which reaches underneath the succeeding one, from the latter, and in order to remove the switch element from the region of action upon the printing products. Those printing products not to be detached from the imbricated formation are conveyed past the processing station by means of the belt conveyor with their mutual position unaltered. The speed of the accelerating belt and the raising of the extraction arrangement is to be matched exactly to and synchronized with the conveying speed, the size of the printing products, and their overlap. Furthermore, these apparatus are not suitable for the processing of imbricated formations in which the leading edge of each printing product is covered in each case by the preceding printing product.
A further device for the processing of printing products arriving in imbricated formation is known from EP-A 0,096,228 and the corresponding U.S. Pat. No. 4,538,161. The printing products are held individually by grippers of a conveyor in the region of their leading edge running at right angles to the conveying direction, and drawn with their trailing region over a support. They are thus marked (addressed) in the region of the trailing edge.
A further process and a corresponding apparatus for the processing of printing products are known from EP-A1 0,300,179. The printing products are conveyed to a processing station in an imbricated formation in which, viewed in the conveying direction, each printing product lies on the preceding one, the leading and trailing edges, respectively, of the printing products run at right angles to the conveying direction and the side edges are aligned with one another. The processing station has an accelerating device acting mechanically upon the printing products in order to separate the printing products, and a switch device for feeding the separated printing products optionally to one of two belt conveyors following the processing station downstream. A further imbricated formation, which corresponds to the fed imbricated formation, is formed from the individual printing products fed to the belt conveyors. In the processing station, the printing products retain their position with respect to the conveying direction. In order to be able to deflect the printing products fed in imbricated formation, these printing products must first be exposed by separation, which entails for processing considerable expense and the destruction every time of the fed imbricated formation.
An apparatus for applying safety stitching to a corner region of printing products is known from German Patent Specification 590,480. The multi-sheet printing products are delivered in imbricated formation by means of a star-shaped delivery wheel onto a belt conveyor running at 45.degree. transverse to the axis of the wheel. In the imbricated formation, each printing product lies on the preceding one and the edges of the printing products run at an angle with respect to the conveying direction of the belt conveyor. The corner regions, exposed and projecting laterally from the belt conveyor, of the printing products are stitched by a sewing machine (safety stitching) and the thread between the successive stitched printing products is subsequently cut. The printing products are deflected to form an imbricated formation for further processing in which the leading edges run at right angles to the conveying direction.
German Offenlegungsschrift 3,335,140 and German Auslegeschrift 2,027,422 furthermore disclose apparatus for branching off printed sheets or newspapers fed in an imbricated formation. In this imbricated formation, the leading edges, viewed in the conveying direction, of the printing products run at right angles to the conveying direction and the side edges are aligned with one another. The printing products to be branched off are conveyed, approximately in the direction of one of their diagonals, just in a transition section, such that they are inclined with respect to their conveying direction in the transition section. The sole purpose of this incline is to form a further imbricated formation, which corresponds to the original imbricated formation, from the branched-off printing products on the conveyor following downstream respectively and whose conveying direction runs parallel to the feed direction.
U.S. Pat. No. 3,239,676 furthermore discloses an apparatus for the contactless counting by means of a light barrier of signature sheets conveyed in an imbricated formation. This apparatus has a first belt conveyor on which the signature sheets are arranged in an imbricated formation in which each signature sheet lies on the preceding one and the side edges of the signature sheets are aligned with one another parallel to the conveying direction of this belt conveyor. At the end of the first belt conveyor, the signature sheets drop onto a second belt conveyor whose conveying direction runs offset to the conveying direction of the first belt conveyor, viewed in a horizontal plane, by 45.degree. and whose conveying speed is greater than the conveying speed of the first belt conveyor. An imbricated formation is thus formed on the second belt conveyor in which the edges of the signature sheets run rotated through 45.degree. with respect to the conveying direction of this second belt conveyor and in which the distance between corresponding edges of successive signature sheets is increased. In the region of one edge of this imbricated formation, thus running with a sawtooth shape, the light barrier is arranged, the light beam of which is interrupted by a corner region of each signature sheet forming a tooth of this edge. At the end of the second belt conveyor, the signature sheets drop onto a further belt conveyor whose conveying direction runs parallel to the conveying direction of the first belt conveyor and whose conveying speed is the same as the conveying speed of the first belt conveyor, in order to form an imbricated formation which corresponds exactly to the fed imbricated formation from the first belt conveyor.
All these apparatus known from German Offenlegungsschrift 3,335,140, from German Auslegeschrift 2,027,442 and from U.S. Pat. No. 3,239,676 have the common feature that in the region in which the edges of the sheets or newspapers run at an angle with respect to their temporary conveying direction, no influence is exerted, so as not to disturb the formation and so as to ensure the conveying away in an imbricated formation which corresponds to the fed imbricated formation.